Many magnetic-field sensors, such as Hall-effect elements, magnetotransistors, magfets, and magneto-diodes are known from the prior art. An example of a magnetically sensitive semiconductor device is disclosed in U.S. Pat. No. 4,100,563. Such magnetic field sensing devices usually have relatively low sensitivites to changes in magnetic field intensity. In addition, such devices may be non-linear and temperature-sensitive. It is the object of this invention to use relatively simple circuitry in connection with known magnetic field sensing devices, to achieve a magnetic-field sensing circuit which is linearly responsive to changes in magnetic-field intensity and relatively independent of temperature changes.